With the gradual maturity of China's hydraulic pressure, there are various types of pressure switches. The specific models are WMAP, mjcs, DNA, JCS, DNP, DNF, DNB, map, hed4 and hed8, etc. each has its own advantages. The selection should refer to the equipment requirements. Tips: pressure relay can sense the pressure of system fluid and send out switch signal. When the pressure reaches the set value, the normally open contact closes and the normally closed contact opens. We can make good use of this function programmatically. But in the actual use, we will encounter some problems. We should choose high visibility, many years of practice, product quality assurance, if we buy the poor cheap, waste money is a small matter, but also delay the production progress of their own equipment. Our company has been producing pressure relay for 18 years, with reliable quality. At the same time, we welcome colleagues to communicate with each other.